I kept traveling without any exact destination in mind. No map or GPS... I was just relying on a few vague directions.
If I could at least remember the names of the places where canon events happened, this would be way easier. But knowing they exist isn't the same as knowing where the hell they are.
I know Tanjiro ran into Muzan in Tokyo, which is also where Tamayo was, along with the Entertainment District and Doma's cult. Everything else was a blank space, even though I know the Final Selection takes place on a mountain owned by the Demon Slayer Corps, and that the former Water Hashira trained Tanjiro on a different mountain, still somewhere in the Kanto region.
For now, I just kept heading east. In Japan, going east solves half your problems. If I were in that aggressive neighboring country, I'd go west instead... even if only to honor the legends.
The trail shifted between open fields and dense forest patches. Sometimes I could see mountains in the distance, sometimes it was just trees swallowing the sky.
That same day after leaving the village, I officially started training with the smallest gourd.
The training to achieve Constant Total Concentration was… blowing into the gourd until it breaks.
Simple enough, but physiologically kind of brutal.
I stopped in a small clearing near a stream. I set my backpack on a rock and picked up the smallest of the three gourds.
"Alright… let's do this."
I pressed my mouth to the opening and inhaled deeply. 'Total Concentration.'
Then I blew the air in, the sound echoing inside the gourd. I kept going until my head started pounding and my body screamed for oxygen.
"… This is harder than it looks."
My lungs were stronger than normal, enhanced by the Physical upgrade, but actually maximizing their use was still work.
So I kept trying, failing and repeating.
After the tenth attempt, my head started spinning. I sat down on the rock, breathing heavily.
"This is basically lung weightlifting."
I opened the Employee Profile screen and saw that Total Concentration Breathing had gone up by one point.
"… So this is actually effective."
And with the method confirmed, I just had to keep pushing until it worked.
Almost an hour later, my lungs felt like two burning chunks of coal inside my chest.
The semi-transparent screen appeared.
–––
[Total Concentration Breathing <10/100>
Type: Technique
*Involves inhaling the maximum possible amount of oxygen through specific patterns to drastically increase blood flow and muscular strength.]
–––
It had grown three points in a single hour. Way better than my previous growth rate.
"Now we're talking! The power of grind is real!"
Satisfied, I put the small gourd away, adjusted my backpack and the rest of my gear. Then I returned to the trail, letting my lungs recover while I walked.
...
I spent two more days blowing into that damn gourd like my life depended on it. Which, thinking about it, it probably actually did.
On the morning of the third day, while I was repeating the process for what had to be the hundredth time, thin cracks started spreading across the surface of the gourd and then... it finally split.
I just stood there, still blowing for half a second before realizing what happened. "… Finally, you miserable piece of shit!!"
I let out the remaining air and dropped the broken pieces to the ground, immediately opening the semi-transparent screen.
–––
[Total Concentration Breathing <20/100>
Type: Technique
*Involves inhaling the maximum possible amount of oxygen through specific patterns to drastically increase blood flow and muscular strength.]
–––
The skill had doubled compared to the last time I checked.
And now I could maintain Total Concentration for a few hours without feeling like I was about to pass out, which was already a huge advantage.
I also used those days to train Sword Breathing, but it only went up two points.
Apparently, inventing a style is easier than refining it.
Even so, my cuts were cleaner, and my body no longer stiffened during transitions between movements.
It was still a rough draft, but it was getting better.
A few days later, already working on the medium gourd, I passed through a small village to restock food and water.
I managed to get a bowl of rice, some dried fish, and refilled my water bottles. I also found a place to sleep… which happened to be a farmer's barn.
Maybe it was curiosity about the massive gourd strapped to my back, or caution about the katana at my waist, but he didn't ask many questions.
I didn't offer any answers either.
When exhaustion finally hit, I lay down on some hay bales, using my backpack as a pillow. It didn't take long for my body to relax.
I don't know how long I slept, but I suddenly woke up… and it wasn't from a nightmare.
I could hear screams nearby, and it definitely wasn't an argument.
I sat up for a second, but my body went on alert before my brain fully processed it.
And my heart sped up as reality settled in.
"Here we go again…!!"
I got up, grabbing the katana beside the hay bales and fastening it to my belt.
"Time to work, Misogi!"
I ran out of the barn, figuring out the direction quickly. The screams were coming from the south side of the village, near the more isolated houses.
"Total Concentration!"
Air rushed in, and I focused strength into my legs, exploding forward in a burst and covering a hundred meters in less than a second.
I crossed the village in near darkness, guided only by sound. Some doors were open, a fallen oil lamp cast weak light onto the street.
The noise came from behind the houses, near a small clearing where the trail led back into the forest.
When I rounded the last corner, I finally found the troublemakers.
There were three demon slayers, all wearing the same standard black uniform, already torn in several places. None of them wore flashy haori, and none were any of the Hashira I knew from canon.
In the middle of them stood a tall, thin Oni, its chest looking bloated and its mouth stretched unnaturally wide.
I recognized the danger the moment I saw it.
"Fall back!" one of the demon slayers shouted.
But even with the warning, it was already too late for them. The Oni screamed, and the sound traveled like a wave, the sonic blast spreading out like an invisible impact.
The unseen explosion hit all three slayers at the same time, launching them backward like rag dolls.
One of them slammed into a wooden wall, which cracked from the impact. Another rolled across the ground, clutching his ears. The third tried to keep his stance, but his knees buckled.
'… A sound wave–based Kekkijutsu.'
It looked powerful, but I couldn't help wondering how this Oni would do against the Sound Hashira, Uzui-san.
Judging by the lack of markings in his eyes, he wasn't one of the Twelve Kizuki… so most likely he'd get brutally violated.
The Oni tilted his head in amusement, unaware that I was casually imagining his future death at the hands of the flamboyant Hashira.
"What's wrong? You don't like a little noise?" he mocked, his voice vibrating strangely through the air.
One of the Demon Slayer Corps members stood up first, raising his sword into a high guard and charging.
He slid forward, his katana drawing a fluid arc through the air.
The Oni opened his mouth again, and a concentrated wave slammed straight into the man's chest.
Even from where I stood, I heard the sound of something breaking. Blood poured from the slayer's nose and mouth before he could finish his swing.
"Senpai!" One of the others shouted. He rushed in from the side, twisting his body to attack from a different angle.
The Oni saw him and grinned. "Great! Let's make more noise!"
Another sonic wave erupted, splintering wood from the nearby houses.
The two remaining demon slayers were thrown back again.
One of them dropped his sword, while the other tried to get up… but his whole body trembled, unable to support itself.
Because of the Oni's Kekkijutsu, the demon slayers were getting wrecked with ease.
'What's the best way to deal with a sound wave attack?'
It'd be nice if I could just slice through it, but I doubt it works like that.
'Some kind of super headphones with insane noise canceling?'
Unfortunately, I don't have an online store to place an instant order.
The Oni stepped forward.
"I wanted to test my Kekkijutsu on someone interesting…" he said, almost disappointed. "But you were pathetic."
His chest began inflating again, his ribs expanding like a bellows. "So die, idiots!"
'Total Concentration, Sword Breathing…!'
I exploded sideways, using the burst I'd trained so many times from my bootleg version of Thunder Breathing.
The ground where I'd been standing a second earlier cracked. The pressure grazed my shoulder, like the air itself had shoved me.
I reached his side before he could close his mouth and swung my katana in a clean horizontal cut.
"First Form, Simple Cut."
The blade sank into flesh, cutting deep across his back. His body split at the abdomen before falling apart, the two halves collapsing separately.
"…" That was more effective than I expected.
"Can you guys get away on your own?" I asked, taking my eyes off the Oni and stepping toward the injured demon slayers.
One of them stared at me, still dazed.
"What did you do?!" he shouted. "Why didn't you cut his head?! You were supposed to cut his head!!"
"Because even if I did, he'd regenerate, Demon Slayer-san."
That's why I chose damage that would stall him as much as possible without costing me too much stamina.
The man who took the sonic blast straight to the chest coughed up blood and looked at me with difficulty. "You— you're not part of the organization… are you?"
"Not yet," I admitted, watching some of their eyes widen.
He nodded, like he'd already suspected. With effort, he extended his sword toward me.
"This is a Nichirin blade," he said weakly. "Cut the bastard's head with this… and he'll die for good."
I sheathed my katana and accepted the Nichirin, testing the famous blade for the first time in this world.
His blade had a faint bluish tint, with no kanji engraved.
"Hmm… it's a bit light, but it'll do."
I half expected some dramatic sensation to happen, but I didn't feel anything different.
"Can you move now?" I asked again, getting back to what mattered.
They nodded quickly. One of them supported the injured one by the arm while they exchanged a look.
"Good luck," they said, then started dragging themselves away.
I waved and turned my focus back, watching the Oni almost fully regenerated.
Even splitting his body in half had only stalled him for a minute or two.
"It really is unfair."
I'd love to have regeneration like that. Of course, my desire isn't strong enough to turn me into an Oni.
Finally, the Oni opened his eyes again, looking pretty pissed off. "Insolent human…"
"What's wrong?" I shot back. "Is it only fun when you're the one hurting others?"
Excuse me, but I don't tolerate hypocrisy beyond my own!